1. Field of the Invention
The present invention relates to a bearing assembly in which a raceway ring of a bearing has a different linear expansion coefficient from that of an opposite member or a bearing mounting member to which the raceway ring is mounted.
2. Description of the Relevant Art
A raceway ring of a bearing having a different linear expansion coefficient from an opposite member, such as a bearing box or a shaft on which the raceway ring is mounted, for example, a bearing inner ring made of ceramic secured to a rotary shaft made of steel by using an inner ring clamp and a clamping nut, is disclosed in Japanese Patent Laid-Open Publication No. 61-252917.
In the bearing securing device disclosed in the above-mentioned patent publication, side surfaces of the bearing inner ring made of ceramic and side surfaces (axial end surfaces) of the inner ring clamp are formed to be cones, or either of the side surfaces of the bearing inner ring or the side surfaces of the inner ring clamp are formed to be spheres. The bearing inner ring and the inner ring clamp are brought into close contact with a predetermined contact angle .theta., or into point contact. As a result, when an environmental temperature is changed during use, relative displacements of the bearing inner ring and the inner ring clamp at the contact surface or contact point are equal to each other thereby absorbing a difference in expansion by heat among the shaft, bearing inner ring and inner ring clamp.
In the above-mentioned bearing securing device, the contact angle .theta., when the bearing inner ring and the inner ring clamp are brought into close contact with their side surfaces in the form of cones, is calculated using a relationship which includes a total of seven functions: linear expansion coefficients of the bearing inner ring, inner ring clamp, and shaft; a radius R from the center of the bearing; and widths (axial lengths) of the bearing inner ring, and bearing fixed portion of the shaft, except the inner clamp ring and screw portion, at positions of the radius R.
As a result, in calculating the contact angle .theta., it is necessary to obtain a value of the linear expansion coefficient and an axial length of each of the components, thereby involving significant time and complexity.